U.S. patent application number 10/222878 was filed with the patent office on 2003-06-19 for surface neuroprosthetic device having a locating system.
This patent application is currently assigned to NESS NEUROMUSCULAR ELECTRICAL STIMULATION SYSTEMS LTD.. Invention is credited to Dar, Amit, Nathan, Roger H..
Application Number | 20030114893 10/222878 |
Document ID | / |
Family ID | 23332661 |
Filed Date | 2003-06-19 |
United States Patent
Application |
20030114893 |
Kind Code |
A1 |
Nathan, Roger H. ; et
al. |
June 19, 2003 |
Surface neuroprosthetic device having a locating system
Abstract
A surface neuroprosthetic device for functional electrical
stimulation (FES) having a locating system for locating the device
on to a limb segment of a user, and a method therefor, the device
including: (a) an at least semi-rigid exoskeleton shell for
encompassing at least a portion of the limb segment; (b) at least
one electrical stimulation electrode operatively connected with the
shell, for making electrical contact with a surface of the limb
segment, so as to effect FES of at least one muscle of the limb
segment; and (c) a locator, operatively connected with the shell,
for determining a positioning of the shell relative to the limb
segment, such that the electrode is positioned near an activating
point, the locator including: (i) means for determining rotational
positioning of the exoskeleton shell on the limb segment, and (ii)
means for determining longitudinal positioning of the exoskeleton
shell on the limb segment.
Inventors: |
Nathan, Roger H.; (Herzilia
B, IL) ; Dar, Amit; (Ramot Hashavim, IL) |
Correspondence
Address: |
DR. MARK FRIEDMAN LTD.
c/o Bill Polkinghorn
Discovery Dispatch
9003 Florin Way
Upper Marlboro
MD
20772
US
|
Assignee: |
NESS NEUROMUSCULAR ELECTRICAL
STIMULATION SYSTEMS LTD.
|
Family ID: |
23332661 |
Appl. No.: |
10/222878 |
Filed: |
August 19, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60340277 |
Dec 18, 2001 |
|
|
|
Current U.S.
Class: |
607/48 ; 223/111;
623/24 |
Current CPC
Class: |
A61N 1/0472 20130101;
A61N 1/0492 20130101; A61N 1/0476 20130101; A61N 1/0484 20130101;
A61N 1/36003 20130101; A61N 1/0452 20130101 |
Class at
Publication: |
607/48 ; 623/24;
223/111 |
International
Class: |
A61F 002/70 |
Claims
What is claimed is:
1. A surface neuroprosthetic device for functional electrical
stimulation having a locating system for locating the device on to
a limb segment of a user, the device comprising: (a) an at least
semi-rigid exoskeleton shell for encompassing at least a portion of
the limb segment; (b) at least one electrical stimulation electrode
operatively connected with said shell, said electrode for making
electrical contact with a surface of the limb segment, so as to
effect functional electrical stimulation (FES) of at least one
muscle of the limb segment; and (c) a locator, operatively
connected with said shell, for determining a positioning of said
shell relative to the limb segment, such that said electrode is
positioned near an activating point of said muscle, said locator
including: (i) means for determining rotational positioning of said
exoskeleton shell on the limb segment, and (ii) means for
determining longitudinal positioning of said exoskeleton shell on
the limb segment.
2. The neuroprosthetic device of claim 1, wherein said locator
further includes means for differentiating between a front side and
a rear side of said shell and means for identifying an orientation
of the device.
3. The neuroprosthetic device of claim 1, wherein said locator
further includes: (iii) means for differentiating between upper and
lower edges of said exoskeleton shell.
4. The neuroprosthetic device of claim 1, wherein said means for
determining rotational positioning include a handle for gripping
the device, said handle defining an orientation of the device, such
that a natural donning motion of a hand holding said handle sets
the device in an approximately correct rotational orientation on
the limb segment.
5. The neuroprosthetic device of claim 1, wherein said means for
determining longitudinal positioning include a handle for gripping
the device, said handle defining a position of the device along the
limb segment, such that a natural donning motion of a hand holding
said handle sets the device in an approximately correct
longitudinal position along the limb segment.
6. The neuroprosthetic device of claim 2, wherein said means for
differentiating between said front side and rear side of said shell
include at least one visual cue.
7. The neuroprosthetic device of claim 6, wherein said at least one
visual cue includes an edge of said front side and an edge of said
rear side, each said edge having a characteristically different
curvilinearity.
8. The neuroprosthetic device of claim 7, wherein said edge of said
front side is generally concave, and wherein said edge of said rear
side is generally convex.
9. The neuroprosthetic device of claim 2 wherein said means for
differentiating include at least one visual cue selected from the
group consisting of colored designs, markings, and logos.
10. The neuroprosthetic device of claim 3, wherein said means for
differentiating between said upper and lower edges include at least
one flap extending from said shell.
11. The neuroprosthetic device of claim 1, wherein said means for
determining rotational positioning of said exoskeleton shell on the
limb segment include flaps longitudinally extending from said
shell.
12. The neuroprosthetic device of claim 11, wherein said flaps are
configured so as to contact surface of the limb segment when the
device is correctly positioned on the limb segment.
13. The neuroprosthetic device of claim 11, wherein said flaps are
configured so as to snugly contact surface of the limb segment when
said electrode is in a correct position near said activating point
and such that rotation of the device away from said position
results in a visually detectable deflection of said flaps
14. The neuroprosthetic device of claim 11, wherein said flaps are
configured so as to snugly contact surface of the limb segment when
said electrode is in a correct position near said activating point
and such that rotation of the device away from said correct
position generates a mechanical torsion resistance for guiding the
user.
15. The neuroprosthetic device of claim 11, wherein said flaps are
disposed in slots in said shell.
16. The neuroprosthetic device of claim 15, wherein said flaps are
disposed in said slots in a reversibly detachable fashion.
17. The neuroprosthetic device of claim 11, wherein said flaps are
designed and configured to be extended from said shell into an
extended position during donning, and to be retracted towards said
shell into a retracted position during use of the device.
18. The neuroprosthetic device of claim 17, said shell further
including securing means for securing said flaps in said retracted
position.
19. The neuroprosthetic device of claim 1, wherein said exoskeleton
shell is designed to encompass at least a portion of an upper arm,
said locating system further including: (iii) flaps extending from
said shell towards an elbow of said arm, said flaps for locating
said exoskeleton shell on each side of said elbow.
20. The neuroprosthetic device of claim 1, wherein said exoskeleton
shell is designed to encompass at least a portion of a lower leg,
said locating system further including: (iii) flaps extending from
said shell towards a knee joint, said flaps for locating said
exoskeleton shell on each side of said knee joint.
21. The neuroprosthetic device of claim 1, wherein said exoskeleton
shell is designed to encompass at least a portion of a lower leg,
and wherein said means for determining rotational positioning
include a mold in said shell, said mold having a shape
corresponding to an inferior surface of a tibial tuberocity of said
lower leg, said mold for aligning with said tibial tuberocity to
determine said rotational positioning of said shell on said lower
leg.
22. The neuroprosthetic device of claim 1, wherein said exoskeleton
shell is designed to encompass at least a portion of a lower leg,
and wherein said means for determining longitudinal positioning
include a mold in said shell, said mold having a shape
corresponding to an inferior surface of a tibial tuberocity of said
lower leg, said mold for aligning with said tibial tuberocity to
determine said longitudinal positioning of said shell on said lower
leg.
23. The neuroprosthetic device of claim 1, wherein said exoskeleton
shell is designed to encompass at least a portion of a lower leg,
and wherein said means for determining rotational positioning and
said means for determining longitudinal positioning include a mold
in said shell, said mold having a shape corresponding to an
inferior border of a patella of said lower leg, said mold for
abutting with said inferior border to determine said rotational
positioning and said longitudinal positioning of said shell on said
lower leg.
24. The neuroprosthetic device of claim 23, wherein said mold has
an adjusting and attaching means such that the mold may be adjusted
to an optimal position to suit an individual patient and then
attached in this position to the shell for subsequent location of
the device by said patient on to the limb segment of said
patient.
25. The neuroprosthetic device of claim 1, wherein said exoskeleton
shell is designed to encompass at least a portion of a lower leg,
and wherein said means for rotational positioning and said means
for longitudinal positioning include at least one long flap
extending down from said shell and over a malleolus of an ankle
joint of said leg, so as to determine said rotational positioning
and said longitudinal positioning of said shell on said leg.
26. The neuroprosthetic device of claim 25, said long flap having
an adjusting and fixing means such that the mold may be adjusted to
an optimal position to suit an individual patient and then attached
in this position to the shell for subsequent location of the device
by said patient on to the limb segment of said patient.
27. The neuroprosthetic device of claim 1, wherein said exoskeleton
shell is designed to encompass at least a portion of a thigh, and
wherein said means for rotational positioning include a flat
locator surface disposed on a posterior exterior surface of said
shell, said flat locator surface for aligning with a flat seat on
which the user is seated during donning of the device.
28. The neuroprosthetic device of claim 1, wherein said exoskeleton
shell is designed to encompass at least a portion of a forearm, and
wherein said means for rotational positioning include a flat
locator surface disposed on an exterior palmar surface of said
shell, said flat locator surface for aligning with a flat reference
surface during donning of the device while aligning, to said flat
reference surface, a plane of a palm of a hand of said forearm.
29. The neuroprosthetic device of claim 16, wherein said shell and
said slots are designed such that said flaps are for attaching to,
and extending from, either longitudinal side of said shell, thereby
enabling utilization of the device in both left-limb and right-limb
applications.
30. A surface neuroprosthetic device for functional electrical
stimulation (FES) having a locating system for locating the device
on to a limb segment of a user, the device comprising: (a) an at
least semi-rigid exoskeleton shell for encompassing at least a
portion of the limb segment; (b) a surface electrode array fixed in
position within said shell, said electrode array for making
electrical contact with a surface of the limb segment, so as to
effect functional electrical stimulation of the limb segment; and
(c) a locating system, operatively connected with said shell, for
identifying the orientation of the device, determining a
positioning of said shell relative to the limb segment, and
facilitating donning of the device at a correct position and
orientation on to the limb segment, said locating system including:
(i) means for determining rotational positioning of said
exoskeleton shell on the limb segment, and (ii) means for
determining longitudinal positioning of said exoskeleton shell on
the limb segment, said locating system being adjusted and attached
to the device during an initial device set-up session to fit the
limb segment of the user.
31. A method of locating a neuroprosthetic device on a limb segment
of a user, the method comprising the steps of: (a) providing a
neuroprosthetic device including: (i) an at least semi-rigid
exoskeleton shell for encompassing at least a portion of the limb
segment; (ii) at least one electrical stimulation electrode
operatively connected with said shell, said electrode for making
electrical contact with a surface of the limb segment, so as to
effect functional electrical stimulation (FES) of at least one
muscle of the limb segment; and (iii) a locating system for
positioning said shell relative to the limb segment, said locating
system including: (A) means for determining rotational positioning
of said exoskeleton shell on the limb segment, and (B) means for
determining longitudinal positioning of said exoskeleton shell on
the limb segment; (b) donning said neuroprosthetic device on the
limb segment; (c) applying said means for determining rotational
positioning such that said neuroprosthetic device is rotationally
positioned near an activating point on the limb segment, and (d)
applying said means for determining longitudinal positioning such
that said neuroprosthetic device is longitudinally positioned near
said activating point on the limb segment.
32. The method of claim 31, wherein the neuroprosthetic device
further includes: (iv) a handle for gripping the device, said
handle defining an orientation of the device, such that a natural
donning motion of a hand holding said handle sets the device in an
approximately correct rotational position on the limb segment,
wherein step (b) is performed by means of said handle, so as to set
the device in said approximately correct rotational position.
33. The method of claim 31, wherein said locating system further
includes flaps longitudinally extending from said shell.
34. The method of claim 33, wherein said flaps are configured so as
to contact surface of the limb segment, the method further
comprising the step of: (e) rotating the device in a vicinity of a
potentially correct position on the limb segment.
35. The method of claim 34, further comprising the step of: (f) if
said rotating the device results in substantially zero mechanical
torsion resistance, identifying said position as a correct
rotational position.
36. The method of claim 35, further comprising the step of: (g) if
said rotating the device results in mechanical torsion resistance,
reapplying step (c).
37. The method of claim 35, further comprising the step of: (g) if
said rotating the device results in said flaps deflecting outwards,
reapplying step (c).
38. The method of claim 36, wherein said exoskeleton shell is
designed to encompass at least a portion of a lower leg.
39. The method of claim 31, wherein said means for determining
rotational positioning include at least two flaps longitudinally
extending from said shell, and wherein the limb segment belongs to
an upper arm.
40. The method of claim 39, wherein step (c) includes rotating an
elbow joint of said arm from extension to flexion, and wherein,
when the device is rotationally aligned, proximal forearm tissue on
said arm contacts said two flaps.
41. The method of claim 31, wherein the limb segment belongs to an
upper arm, said means for determining longitudinal positioning
including at least two flaps longitudinally extending from said
shell, wherein said flaps extend down from said shell and relate to
epicondyles of an elbow of said arm to establish a longitudinal
position along a long axis of the device.
42. The method of claim 39, wherein step (c) includes rotating an
elbow joint of said arm from extension to flexion, and wherein,
when the device is incorrectly positioned, a flexing of said elbow
causes at least one of said flaps to be deflected outwards away
from the limb segment by soft tissue of a proximal forearm
associated with said upper arm.
43. The method of claim 31, wherein the limb segment belongs to a
lower leg, wherein a mold in said shell has a shape corresponding
to an inferior surface of a tibial tuberocity of said leg, and
wherein step (c) includes aligning said mold with said tibial
tuberocity to establish rotational positioning of said shell on
said leg.
44. The method of claim 35, wherein step (d) includes aligning said
mold with said tibial tuberocity to establish longitudinal
positioning of said shell on said leg.
45. The method of claim 31, wherein the limb segment belongs to a
lower leg, wherein a mold in said shell has a shape corresponding
to an inferior surface of a tibial tuberocity of said leg, and
wherein step (d) includes aligning said mold with said tibial
tuberocity to establish longitudinal positioning of said shell on
said leg.
46. The method of claim 31, wherein the limb segment belongs to a
lower leg, wherein a mold in said shell has a shape corresponding
to an inferior border of a patella of said leg, and wherein step
(c) includes abutting said inferior border with said mold to
establish rotational positioning of said shell on said leg.
47. The method of claim 31, wherein the limb segment belongs to a
lower leg, wherein a mold in said shell has a shape corresponding
to an inferior border of a patella of said leg, and wherein step
(d) includes abutting said inferior border with said mold to
establish longitudinal positioning of said shell on said leg.
48. The method of claim 31, wherein the limb segment belongs to a
lower leg, wherein said means for rotational positioning and said
means for longitudinal positioning include at least one long flap
extending down from said shell and over a malleolus of an ankle
joint of said leg, and wherein step (c) and step (d) include
aligning said flap with said malleolus to establish rotational and
longitudinal positioning of said shell on said leg.
49. The method of claim 31, wherein the limb segment is a thigh
segment, wherein said exoskeleton shell encompasses at least a
portion of said thigh segment, and wherein said means for
rotational positioning include a flat locator surface disposed on a
posterior exterior surface of said shell, the method further
comprising the step of: (e) sitting the user on a flat seat in a
predetermined seating posture during said donning of the device,
such that said flat locator surface contacts said flat seat,
wherein step (c) includes aligning said flat locator surface with
said flat seat to establish rotational positioning of said shell on
said upper leg.
50. The method of claim 31, wherein the limb segment belongs to a
forearm, wherein said exoskeleton shell encompasses at least a
portion of said forearm, and wherein said means for rotational
positioning include a flat locator surface disposed on a posterior
exterior surface of said shell, wherein step (c) includes resting a
palm of a hand of said forearm on to said flat surface and aligning
said flat locator surface and said palm with said flat surface to
establish rotational positioning of said shell on said forearm.
51. A method of locating a neuroprosthetic device on a limb segment
of a user, the method comprising the steps of: (a) providing a
neuroprosthetic device including: (i) an at least semi-rigid
exoskeleton shell for encompassing at least a portion of the limb
segment; (ii) a surface electrode array fixed in position within
said shell, said electrode array for making electrical contact with
a surface of the limb segment, so as to effect functional
electrical stimulation (FES) of the limb segment, and (iii) a
locating system, operatively connected with said shell, said
locating system including: (A) means for determining rotational
positioning of said exoskeleton shell on the limb segment; (b)
adjusting and attaching said locating system to the device during
an initial device set-up session, so as to position said
neuroprosthetic device to activate effectively the limb segment of
the user; (c) subsequently donning said neuroprosthetic device on
the limb segment, and (d) applying said means for determining
rotational positioning such that said exoskeleton shell and fixed
electrode array is rotationally positioned to activate effectively
the limb segment of the user.
52. The method of claim 51 wherein said locating system further
includes: (B) means for determining longitudinal positioning of
said exoskeleton shell on the limb segment; the method further
comprising the steps of: (e) applying said means for determining
longitudinal positioning such that said exoskeleton shell and said
fixed electrode array are longitudinally positioned to activate
effectively the limb segment of the user.
Description
[0001] This application draws priority from U.S. Provisional Patent
Application Serial No. 60/340,277, filed Dec. 18, 2001.
FIELD AND BACKGROUND OF THE INVENTION
[0002] The present invention relates to a surface neuroprosthetic
device for Functional Electrical Stimulation (FES) of impaired
limbs, and more particularly, to a surface neuroprosthetic device
having a locating system for accurate, facile, and repeatable
locating of the device on to the limb, and the device electrodes on
to the motor points of the muscles thereof.
[0003] FES is a means to communicate with the neuromuscular system
for producing contraction in muscles or sensory input to the body.
FES is used in neuroprostheses for restoring active function to
paralyzed or plegic body limbs in patients suffering disease or
trauma to the central nervous system, in neurological conditions
such as stroke, spinal cord injury, head injury, cerebral palsy and
multiple sclerosis. Surface FES systems use controlled electrical
currents through electrodes placed on the surface of the body, in
order to trigger contraction from muscles underlying the electrode
or to input sensory stimulus. Surface neuroprostheses can
coordinate the FES-activation of several muscles of the limb alone,
or in coordination with voluntary activation of muscles under
natural neurological control. Surface neuroprostheses are in use
today for functional activities such as walking, standing,
gripping/releasing objects, etc.
[0004] Electrode placement is an important issue for surface
neuroprostheses. The patient or his caretaker is required to set up
the neuroprosthesis each time he wishes to use it. This involves
ensuring that all the electrodes are positioned accurately over the
motor points of the muscles to be activated. Accurate electrode
positioning ensures activation of the correct muscle without
overflow to unwanted muscles, sensory tolerance of the stimulation
current intensity needed to produce the desired response, and the
quality of the muscle contraction. A critical factor in surface
neuroprosthesis design is the provision of a means to reduce the
prohibitive time and high expertise required to position the array
of electrodes required to produce complex movement patterns.
[0005] Accurate electrode positioning has proved a barrier to the
use of this technology and has, to date, limited the use of the
surface neuroprosthesis.
[0006] In order to position an exoskeleton on to a body site (also
referred to herein as "limb") quickly, accurately and repeatedly,
some means must be provided to ensure correct position and
orientation of the exoskeleton relative to the body site. We refer
to this means as a "locator".
[0007] Ordinarily, devices that conform to the shape of a
particular body site enable more facile positioning of the
electrodes over the activation points. U.S. Pat. No. 4,432,368 to
Russek describes a locator for a transcutaneous nerve stimulation
(TENS) device for applying sensory FES to the lower back region, in
order to provide pain relief. The electrodes are mounted on a
garment which itself locates by tactile feedback on to bony
landmarks: the iliac crest and the sacro-coccygeal joint. The
sacro-coccygeal landmark is outside the visual field of the device
user, and tactile feedback is the means used for locating the
device.
[0008] U.S. Pat. No. 5,643,332 to Stein discloses a surface
neuroprosthesis device for the lower limb, in which a band housing
the device components is placed on to the lower leg and is located
on to the tibia by a V-shaped metal plate used to position the
device in a circumferential fashion. The locator angle can be bent
during the initial device set-up session to fit individual
patients. No longitudinal location of the V-shaped metal plate is
provided for positioning the device along the longitudinal axis of
the limb.
[0009] U.S. Pat. No. 5,330,516 to Nathan describes an upper limb
neuroprosthesis locator. The device includes a semi-rigid
exoskeleton whereby the surface electrodes are carefully
positioned, by an expert, within the inside surface of the
exoskeleton during an initial fitting session. Subsequently, the
device user places the exoskeleton on to his arm, locating,
firstly, the distal spiral portion of the device on to the bony
mass of his hand, and then placing the proximal portion of the
device around his forearm. The entire electrode array is
constrained for accurate positioning over the limb surface,
according to the electrode placement of the expert. The spiral
locator allows this accurate donning of the electrode array by
utilizing the underlying bone structure of the forearm and
hand.
[0010] Both the leg device disclose by Stein in U.S. Pat. No.
5,643,332 and the upper limb device of Nathan (U.S. Pat. No.
5,330,516) require initial device set-up to be carried out by an
expert, who positions the electrodes in the device to elicit
optimal muscle contraction from the individual patient. The
electrode positioning procedure requires a high degree of skill in
the art in order to set up a full electrode array in an optimal
manner. It would be advantageous to have a device and a method of
implementing the device, which allow the surface electrode array to
be manufactured in a fixed position within the device. This enables
pre-arranging the surface electrode array optimally, one electrode
with respect to each other, and reduces the dependence on the high
degree of skill, artistry, and experience required of the clinician
to carry out the initial electrode set-up procedure. The initial
device set-up procedure would now be reversed with respect to the
prior art: the device housing the entire electrode array is placed
on the limb and adjusted to the optimal position, then locator
system is positioned and attached to the device, such that the
device can be repeatably located to this optimal position by the
patient. This would require the provision of fast accurate means
for positioning the device longitudinally as well as
circumferentially on to a conical upper or lower limb segment.
[0011] It is thus manifest that fast and accurate electrode
positioning has proved to be a problematic issue of central
importance to the implementation of surface neuroprostheses.
Moreover, neurological deficits such as perceptual or motor
deficiencies may affect the requirements of the locator system.
[0012] Perceptual difficulties in neurological conditions such as
stroke can often present a challenge to recognition of device
orientation in space relative to the limb. Here the problem is to
provide a means for making the device orientation and any
rotation-maneuver required for donning the device on a limb
"obvious", fast and easy.
[0013] In addition, motor deficiency can take the form of limb
weakness, paralysis or spasticity, which make donning the device a
challenge. In hemiplegia resulting from stroke or brain injury, the
side of the body on which the neuroprosthesis is donned is often
plegic. The donning action must often be carried out using solely
the contra-lateral non-plegic hand. The posture of plegic limb is
often problematic where spasticity results in reduced voluntary
movements and also limited passive mobility of the limb. The limb
can be set at the extreme of its range of motion, for example, full
adduction at the shoulder joint resulting in the upper arm being
held tightly against the trunk. This abnormal limb posture and lack
of limb mobility can present biomechanical problems in donning the
device and locating it on to the limb.
[0014] It is further noted that the limitations and deficiencies of
known surface neuroprostheses devices are particularly glaring
regarding upper-arm surface neuroprosthesis applications. To the
best of our knowledge, no upper-arm surface neuroprosthesis device
has been successfully developed heretofore.
[0015] There is therefore a recognized need for, and it would be
highly advantageous to have, a neuroprosthetic device and method
for functional electrical stimulation of impaired limbs having a
reliable locating system that provides for accurate, facile,
simple, fast and repeatable positioning and orientation of the
device over the activation points of the muscles, such that the FES
is effective and comfortable.
SUMMARY OF THE INVENTION
[0016] The present invention is a neuroprosthetic device for
functional electrical stimulation of impaired limbs having a
locating system for accurate, facile, and repeatable positioning of
the device on the activating points of the muscles.
[0017] According to the teachings of the present invention there is
provided a surface neuroprosthetic device for functional electrical
stimulation having a locating system for locating the device on to
a limb segment of a user, the device including: (a) an at least
semi-rigid exoskeleton shell for encompassing at least a portion of
the limb segment; (b) at least one electrical stimulation electrode
operatively connected with the shell, the electrode for making
electrical contact with a surface of the limb segment, so as to
effect functional electrical stimulation (FES) of at least one
muscle of the limb segment; and (c) a locator, operatively
connected with the shell, for determining a positioning of the
shell relative to the limb segment, such that the electrode is
positioned near an activating point of the muscle, the locator
including: (i) means for determining rotational positioning of the
exoskeleton shell on the limb segment, and (ii) means for
determining longitudinal positioning of the exoskeleton shell on
the limb segment.
[0018] According to another aspect of the present invention there
is provided a surface neuroprosthetic device for (FES) having a
locating system for locating the device on to a limb segment of a
user, the device including: (a) an at least semi-rigid exoskeleton
shell for encompassing at least a portion of the limb segment; (b)
a surface electrode array fixed in position within the shell, the
electrode array for making electrical contact with a surface of the
limb segment, so as to effect functional electrical stimulation of
the limb segment; and (c) a locating system, operatively connected
with the shell, for identifying the orientation of the device,
determining a positioning of the shell relative to the limb
segment, and facilitating donning of the device at a correct
position and orientation on to the limb segment, the locating
system including: (i) means for determining rotational positioning
of the exoskeleton shell on the limb segment, and (ii) means for
determining longitudinal positioning of the exoskeleton shell on
the limb segment, the locating system being adjusted and attached
to the device during an initial device set-up session to fit the
limb segment of the user.
[0019] According to another aspect of the present invention there
is provided a method of locating a neuroprosthetic device on a limb
segment of a user, the method including the steps of: (a) providing
a neuroprosthetic device including: (i) an at least semi-rigid
exoskeleton shell for encompassing at least a portion of the limb
segment; (ii) at least one electrical stimulation electrode
operatively connected with the shell, the electrode for making
electrical contact with a surface of the limb segment, so as to
effect functional electrical stimulation (FES) of at least one
muscle of the limb segment; and (iii) a locating system for
positioning the shell relative to the limb segment, the locating
system including: (A) means for determining rotational positioning
of the exoskeleton shell on the limb segment, and (B) means for
determining longitudinal positioning of the exoskeleton shell on
the limb segment; (b) donning the neuroprosthetic device on the
limb segment; (c) applying the means for determining rotational
positioning such that the neuroprosthetic device is rotationally
positioned near an activating point on the limb segment, and (d)
applying the means for determining longitudinal positioning such
that the neuroprosthetic device is longitudinally positioned near
the activating point on the limb segment.
[0020] According to another aspect of the present invention there
is provided a of locating a neuroprosthetic device on a limb
segment of a user, the method including the steps of: (a) providing
a neuroprosthetic device including: (i) an at least semi-rigid
exoskeleton shell for encompassing at least a portion of the limb
segment; (ii) a surface electrode array fixed in position within
the shell, the electrode array for making electrical contact with a
surface of the limb segment, so as to effect functional electrical
stimulation (FES) of the limb segment, and (iii) a locating system,
operatively connected with the shell, the locating system
including: (A) means for determining rotational positioning of the
exoskeleton shell on the limb segment; (b) adjusting and attaching
the locating system to the device during an initial device set-up
session, so as to position the neuroprosthetic device to activate
effectively the limb segment of the user; (c) subsequently donning
the neuroprosthetic device on the limb segment, and (d) applying
the means for determining rotational positioning such that the
exoskeleton shell and fixed electrode array is rotationally
positioned to activate effectively the limb segment of the
user.
[0021] According to features in the described preferred
embodiments, the locator further includes means for differentiating
between a front side and a rear side of the shell and for
identifying an orientation of the device.
[0022] According to further features in the described preferred
embodiments, the locator further includes: (iii) means for
differentiating between upper and lower edges of the exoskeleton
shell.
[0023] According to further features in the described preferred
embodiments, the means for determining rotational positioning
include a handle for gripping the device, the handle defining an
orientation of the device, such that a natural donning motion of a
hand holding the handle sets the device in an approximately correct
rotational orientation on the limb segment.
[0024] According to further features in the described preferred
embodiments, the means for determining longitudinal positioning
include a handle for gripping the device, the handle defining a
position of the device along the limb segment, such that a natural
donning motion of a hand holding the handle sets the device in an
approximately correct longitudinal position along the limb
segment.
[0025] According to further features in the described preferred
embodiments, the means for differentiating between the front side
and rear side of the shell include at least one visual cue.
[0026] According to further features in the described preferred
embodiments, the at least one visual cue includes an edge of the
front side and an edge of the rear side, each edge having a
characteristically different curvilinearity.
[0027] According to further features in the described preferred
embodiments, the edge of the front side is generally concave, and
the edge of the rear side is generally convex.
[0028] According to further features in the described preferred
embodiments, the means for differentiating between a front side and
a rear side of the shell and for identifying an orientation of the
device include at least one visual cue selected from the group
consisting of colored designs, markings, and logos.
[0029] According to further features in the described preferred
embodiments, the means for differentiating between the upper and
lower edges include at least one flap extending from the shell.
[0030] According to further features in the described preferred
embodiments, the means for determining rotational positioning of
the exoskeleton shell on the limb segment include flaps
longitudinally extending from the shell.
[0031] According to further features in the described preferred
embodiments, the flaps are configured so as to contact surface of
the limb segment when the device is correctly positioned on the
limb segment.
[0032] According to further features in the described preferred
embodiments, the flaps are configured so as to snugly contact
surface of the limb segment when the electrode is in a correct
position near the activating point and such that rotation of the
device away from the position results in a visually detectable
deflection of the flaps
[0033] According to further features in the described preferred
embodiments, the flaps are configured so as to snugly contact
surface of the limb segment when the electrode is in a correct
position near the activating point and such that rotation of the
device away from the correct position generates a mechanical
torsion resistance for guiding the user.
[0034] According to further features in the described preferred
embodiments, the flaps are disposed in slots in the shell.
[0035] According to further features in the described preferred
embodiments, the flaps are disposed in the slots in a reversibly
detachable fashion.
[0036] According to further features in the described preferred
embodiments, the flaps are designed and configured to be extended
from the shell into an extended position during donning, and to be
retracted towards the shell into a retracted position during use of
the device.
[0037] According to further features in the described preferred
embodiments, the shell further including securing means for
securing the flaps in the retracted position.
[0038] According to further features in the described preferred
embodiments, the exoskeleton shell is designed to encompass at
least a portion of an upper arm, the locating system further
including: (iii) flaps extending from the shell towards an elbow of
the arm, the flaps for locating the exoskeleton shell on each side
of the elbow.
[0039] According to further features in the described preferred
embodiments, the exoskeleton shell is designed to encompass at
least a portion of a lower leg, the locating system further
including: (iii) flaps extending from the shell towards a knee
joint, the flaps for locating the exoskeleton shell on each side of
the knee joint.
[0040] According to further features in the described preferred
embodiments, the exoskeleton shell is designed to encompass at
least a portion of a lower leg, and wherein the means for
determining rotational positioning include a mold in the shell, the
mold having a shape corresponding to an inferior surface of a
tibial tuberocity of the lower leg, the mold for aligning with the
tibial tuberocity to determine the rotational positioning of the
shell on the lower leg.
[0041] According to further features in the described preferred
embodiments, the exoskeleton shell is designed to encompass at
least a portion of a lower leg, and wherein the means for
determining longitudinal positioning include a mold in the shell,
the mold having a shape corresponding to an inferior surface of a
tibial tuberocity of the lower leg, the mold for aligning with the
tibial tuberocity to determine the longitudinal positioning of the
shell on the lower leg.
[0042] According to further features in the described preferred
embodiments, the exoskeleton shell is designed to encompass at
least a portion of a lower leg, and wherein the means for
determining rotational positioning and the means for determining
longitudinal positioning include a mold in the shell, the mold
having a shape corresponding to an inferior border of a patella of
the lower leg, the mold for abutting with the inferior border to
determine the rotational positioning and the longitudinal
positioning of the shell on the lower leg.
[0043] According to further features in the described preferred
embodiments, the mold has an adjusting and attaching means such
that the mold may be adjusted to an optimal position to suit an
individual patient and then attached in this position to the shell
for subsequent location of the device by the patient on to the limb
segment of the patient.
[0044] According to further features in the described preferred
embodiments, the exoskeleton shell is designed to encompass at
least a portion of a lower leg, and wherein the means for
rotational positioning and the means for longitudinal positioning
include at least one long flap extending down from the shell and
over a malleolus of an ankle joint of the leg, so as to determine
the rotational positioning and the longitudinal positioning of the
shell on the leg.
[0045] According to further features in the described preferred
embodiments, the long flap has an adjusting and fixing means such
that the mold may be adjusted to an optimal position to suit an
individual patient and then attached in this position to the shell
for subsequent location of the device by the patient on to his limb
segment.
[0046] According to further features in the described preferred
embodiments, the exoskeleton shell is designed to encompass at
least a portion of a thigh, and the means for rotational
positioning include a flat locator surface disposed on a posterior
exterior surface of the shell, the flat locator surface for
aligning with a flat seat on which the user is seated during
donning of the device.
[0047] According to further features in the described preferred
embodiments, the exoskeleton shell is designed to encompass at
least a portion of a forearm, and the means for rotational
positioning include a flat locator surface disposed on an exterior
palmar surface of the shell, the flat locator surface for aligning
with a flat reference surface during donning of the device while
aligning, to the flat reference surface, a plane of a palm of a
hand of the forearm.
[0048] According to further features in the described preferred
embodiments, the shell and the slots are designed such that the
flaps are for attaching to, and extending from, either longitudinal
side of the shell, thereby enabling utilization of the device in
both left-limb and right-limb applications.
[0049] According to further features in the described preferred
embodiments, the neuroprosthetic device further includes: (iv) a
handle for gripping the device, the handle defining an orientation
of the device, such that a natural donning motion of a hand holding
the handle sets the device in an approximately correct rotational
position on the limb segment, wherein step (b) is performed by
means of the handle, so as to set the device in the approximately
correct rotational position.
[0050] According to further features in the described preferred
embodiments, the locating system further includes flaps
longitudinally extending from the shell.
[0051] According to further features in the described preferred
embodiments, the flaps are configured so as to contact surface of
the limb segment, the method further including the step of: (e)
rotating the device in a vicinity of a potentially correct position
on the limb segment.
[0052] According to further features in the described preferred
embodiments, the method further includes the step of: (f) if
rotating the device results in substantially zero mechanical
torsion resistance, identifying the position as a correct
rotational position.
[0053] According to further features in the described preferred
embodiments, the method further includes the step of: (g) if
rotating the device results in mechanical torsion resistance,
reapplying step (c).
[0054] According to further features in the described preferred
embodiments, method of further includes the step of: (g) if
rotating the device results in the flaps deflecting outwards,
reapplying step (c).
[0055] According to further features in the described preferred
embodiments, the exoskeleton shell is designed to encompass at
least a portion of a lower leg.
[0056] According to further features in the described preferred
embodiments, the means for determining rotational positioning
include at least two flaps longitudinally extending from the shell,
and the limb segment belongs to an upper arm.
[0057] According to further features in the described preferred
embodiments, step (c) includes rotating an elbow joint of the arm
from extension to flexion, and wherein, when the device is
rotationally aligned, proximal forearm tissue on the arm contacts
the two flaps.
[0058] According to further features in the described preferred
embodiments, the limb segment belongs to an upper an, the means for
determining longitudinal positioning including at least two flaps
longitudinally extending from the shell, wherein the flaps extend
down from the shell and relate to epicondyles of an elbow of the
arm to establish a longitudinal position along a long axis of the
device.
[0059] According to further features in the described preferred
embodiments, step (c) includes rotating an elbow joint of the arm
from extension to flexion, wherein, when the device is incorrectly
positioned, a flexing of the elbow causes at least one of the flaps
to be deflected outwards away from the limb segment by soft tissue
of a proximal forearm associated with the upper arm.
[0060] According to further features in the described preferred
embodiments, the the limb segment belongs to a lower leg, wherein a
mold in the shell has a shape corresponding to an inferior surface
of a tibial tuberocity of the leg, and wherein step (c) includes
aligning the mold with the tibial tuberocity to establish
rotational positioning of the shell on the leg.
[0061] According to further features in the described preferred
embodiments, the step (d) includes aligning the mold with the
tibial tuberocity to establish longitudinal positioning of the
shell on the leg.
[0062] According to further features in the described preferred
embodiments, the limb segment belongs to a lower leg, wherein a
mold in the shell has a shape corresponding to an inferior surface
of a tibial tuberocity of the leg, and wherein step (d) includes
aligning the mold with the tibial tuberocity to establish
longitudinal positioning of the shell on the leg.
[0063] According to further features in the described preferred
embodiments, the limb segment belongs to a lower leg, wherein a
mold in the shell has a shape corresponding to an inferior border
of a patella of the leg, and wherein step (c) includes abutting the
inferior border with the mold to establish rotational positioning
of the shell on the leg.
[0064] According to further features in the described preferred
embodiments, the wherein the limb segment belongs to a lower leg,
wherein a mold in the shell has a shape corresponding to an
inferior border of a patella of the leg, and wherein step (d)
includes abutting the inferior border with the mold to establish
longitudinal positioning of the shell on the leg.
[0065] According to further features in the described preferred
embodiments, the limb segment belongs to a lower leg, wherein the
means for rotational positioning and the means for longitudinal
positioning include at least one long flap extending down from the
shell and over a malleolus of an ankle joint of the leg, and
wherein step (c) and step (d) include aligning the flap with the
malleolus to establish rotational and longitudinal positioning of
the shell on the leg.
[0066] According to further features in the described preferred
embodiments, the limb segment is a thigh segment, wherein the
exoskeleton shell encompasses at least a portion of the thigh
segment, and wherein the means for rotational positioning include a
flat locator surface disposed on a posterior exterior surface of
the shell, the method further including the step of: (e) sitting
the user on a flat seat in a predetermined seating posture during
the donning of the device, such that the flat locator surface
contacts the flat seat, wherein step (e) includes aligning the flat
locator surface with the flat seat to establish rotational
positioning of the shell on the upper leg.
[0067] According to further features in the described preferred
embodiments, the limb segment belongs to a forearm, wherein the
exoskeleton shell encompasses at least a portion of the forearm,
and wherein the means for rotational positioning include a flat
locator surface disposed on a posterior exterior surface of the
shell, wherein step (c) includes resting a palm of a hand of the
forearm on to the flat surface and aligning the flat locator
surface and the palm with the flat surface to establish rotational
positioning of the shell on the forearm.
[0068] According to further features in the described preferred
embodiments, locating system further includes: (B) means for
determining longitudinal positioning of the exoskeleton shell on
the limb segment; the method further including the steps of: (e)
applying the means for determining longitudinal positioning such
that the exoskeleton shell and the fixed electrode array are
longitudinally positioned to activate effectively the limb segment
of the user.
[0069] As used herein in the specification and in the claims
section that follows, the term "activation point" and the like
refer to a location on a limb for receiving current from a surface
electrode, so as to achieve functional electrical stimulation. It
must be emphasized that the position and nature of the activation
points depend on the individual patient and on the judgment of the
clinician setting up the device. Electrodes may be positioned
directly on the muscle motor points, or at some distance from the
motor points over regions of the muscle body where the response to
FES may be less strong, but more stable. The electrode may even be
positioned over non-excitable motor regions where motor response is
avoided, for example to elicit a sensory stimulation input only to
the limb.
[0070] Sensors in the neuroprosthesis may also affect the
positioning of the neuroprosthesis on the limb. Here the
positioning of the neuroprosthesis on the limb, and hence the
sensor, may be critical in monitoring the response of the limb to
the limb activation.
[0071] The structure of the neuroprosthesis is also required to
locate on to the limb in the position and orientation such that the
device is self-supporting in a mechanically stable fashion on the
limb even during dynamic limb articulations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0072] The invention is herein described, by way of example only,
with reference to the accompanying drawings. With specific
reference now to the drawings in detail, it is stressed that the
particulars shown are by way of example and for purposes of
illustrative discussion of the preferred embodiments of the present
invention only, and are presented in the cause of providing what is
believed to be the most useful and readily understood description
of the principles and conceptual aspects of the invention. In this
regard, no attempt is made to show structural details of the
invention in more detail than is necessary for a fundamental
understanding of the invention, the description taken with the
drawings making apparent to those skilled in the art how the
several forms of the invention may be embodied in practice.
[0073] In the drawings:
[0074] FIG. 1 is a schematic diagram of a generic exoskeleton
device encompassing an upper limb;
[0075] FIG. 2 is a perspective front view of an upper arm
neuroprosthetic device having a locating system, and disposed on an
upper arm, according to one aspect of the present invention;
[0076] FIG. 3 is a perspective side view of an inventive lower leg
neuroprosthetic device having a locating system;
[0077] FIG. 4 is a perspective view of another preferred embodiment
of a neuroprosthetic device, disposed on a lower leg, and having a
locating system based on the tibial tuberocity;
[0078] FIG. 5 is a perspective view of another preferred embodiment
of a neuroprosthetic device, disposed on a lower leg, and having a
locating system based on the patella;
[0079] FIG. 6 is a perspective view of another preferred embodiment
of a neuroprosthetic device, disposed on a lower leg, and having a
locating system including flap finders;
[0080] FIG. 7 is a perspective view of an inventive neuroprosthetic
device, disposed on a thigh, for knee-joint activation;
[0081] FIG. 8 is a perspective view of an inventive neuroprosthetic
device having two removable flap finders, and
[0082] FIG. 9 is a perspective view of an inventive neuroprosthetic
device having arrangements for moving the locator out of the
way.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0083] The present invention is a neuroprosthetic device for
functional electrical stimulation of impaired limbs having a
locating system for accurate, facile, and repeatable positioning of
the device on the activating points of the muscles.
[0084] As used herein in the specifications and in the claims
section that follows, the tern "locating system" or "locator"
refers to a system for accurate, fast and repeatable positioning of
a FES device on the limb of a patient. The locating system assures
correct position and orientation of a rigid or semi-rigid
exoskeleton relative to the limb, thereby positioning the
electrodes integrated into the device in an accurate, fast and
repeatable manner over the sites selected to activate the limb
muscles.
[0085] The principles and operation of the present invention may be
better understood with reference to the drawings and the
accompanying description.
[0086] Before explaining at least one embodiment of the invention
in detail, it is to be understood that the invention is not limited
in its application to the details of construction and the
arrangement of the components set forth in the following
description or illustrated in the drawings. The invention is
capable of other embodiments or of being practiced or carried out
in various ways. Also, it is to be understood that the phraseology
and terminology employed herein is for the purpose of description
and should not be regarded as limiting. Locating rigid or
semi-rigid exoskeleton FES devices on a limb of a user depends on
the specific limb and requires a specific locator that fits the
shape and size of the limb. Usually, locators rely on mechanical
and physical positioning of the device on a mechanical stable
feature of the particular limb segment. Typical examples are
skeletal and bony features underlying the skin surface, and the
axis of rotation of limb joints having one degree of freedom, such
as the elbow or knee.
[0087] FES devices for upper or lower limb segments are basically
tubular in shape, in order to conform to the substantially conical
shape of these limb segments. Referring now to the drawings, FIG. 1
schematically shows a neuroprosthetic device 100 placed on an upper
arm segment 12, as a typical example of a limb segment. Exoskeleton
10 is positioned so as to encompass upper arm segment 12. The
conical form of upper arm segment 12 interacts with the tubular
form of exoskeleton 10. The number of degrees of freedom remaining
between exoskeleton 10 and arm 12 are reduced to 2, fixing the
position and orientation of exoskeleton 10 in all but the angular
orientation 0 of exoskeleton 10 about the long Y-axis of upper arm
segment 12, and the positional location y of exoskeleton 10 along
the long Y-axis of upper arm segment 12.
[0088] The sensitivity of FES device performance to location on the
limb, and particularly to these two degrees of freedom about the
long axis of the limb, is the essence of the problem in the donning
of the device by the user (or by the patient caretaker or family
member) to the limb of the user. Each limb segment has its own
specific anatomical features that might be used for the device
location. Each device user may have disabilities that make the
device donning a particular challenge. The neurological deficits,
mentioned hereinabove, such as perceptual or motor deficiencies,
may affect the requirements of the locating system.
[0089] The locating system of the present invention includes
several components, integrated into the FES neuroprosthetic device,
for facilitating each stage of the donning process, and for
overcoming the various motor and perceptual challenges of the
user.
[0090] One component of the locating system is a geometrical design
of the device especially suitable for users who may be perceptually
challenged. Here, the shape of the device simplifies identification
of device orientation prior to donning, to enable the device to be
placed right side up, and generally facing the right direction.
[0091] In addition, a handle is provided to grip the device in
order to place it on to the plegic limb. The handle defines the
orientation of the device such that when holding the device by the
handle of the locator, and by carrying out a natural motion to
bring the device to the plegic limb, the device immediately locates
on to the limb in approximately the correct position and
orientation.
[0092] Specific components of the locating system enable accurate
positional adjustment of the device along the long axis of the
limb, while other components enable accurate adjustment of the
angular orientation of the device about the long axis of the
limb.
[0093] During initial setting-up of the neuroprosthesis, the
clinician may select or adjust one or more locating means
appropriate for a particular patient. The clinician is not required
to adjust the electrode array. Subsequently, each time the patient
places the device on his arm, the device aligns approximately along
the limb segment in approximately the correct location. The patient
then adjusts the position of the device along the length of the
segment, and the orientation of the device around the segment using
this combination of visual, mechanical and tactile cues provided by
the locating system.
[0094] FIG. 2 provides a perspective view of an upper arm
neuroprosthetic device equipped with a locating system, according
to one aspect of the present invention. The locating system, of
this preferred embodiment, includes various visual and mechanical
components that facilitate the identification of the general
orientation of the device before donning. In this drawing of upper
arm neuroprosthetic device 100, upper concave curved edge 114 and
lower concave curved edge 116 are visual cues used to identify the
front panel 118 of device 100, and to differentiate from the rear
panel 120, which has convex-shaped edges 122. These cues allow a
perceptually challenged user to identify between the front and rear
of device 100.
[0095] Flaps 124a and 124b extend down from lower edge 116 of
anterior panel 118 to further aid the perceptually challenged user
to identify between the upper (proximal) edge 114 and lower
(distal) edge 116 of device 100. Flaps 124a and 124b form, along
with lower edge 116, an easily identifiable arch.
[0096] An additional visual cue for identifying, prior to donning,
the orientation of device 100, is a handle 126 that identifies a
lateral side of device 100. Handle 126 is positioned on device 100
so as to provide visual and tactile aid for the location of device
100 on the arm using the contra-lateral hand to hold handle
126.
[0097] Device 100, as shown in FIG. 2, is intended for a right
upper arm, therefore handle 126 is held by the left hand as device
100 is donned. Keeping the elbow close to the body and bringing
device 100 around and in front of the body, the natural trajectory
introduces device 100 to the plegic arm at approximately the right
position and orientation on upper arm segment 112. Handle 126 now
acts as a mechanical locator within the neuroprosthesis system.
[0098] Device 100 is now approximately in position on upper arm
segment 112. Components of the locating system are next used to
more accurately position device 100 on the limb. Several components
of the locating system, when used together, improve simplicity,
speed and accuracy of the donning of device 100.
[0099] The arch, formed by flaps 124a and 124b together with lower
concave curved edge 116, fits snugly around the distal anterior
portion of upper arm segment 112. The arch, and particularly flaps
124a and 124b, provide a combination of mechanical constraint and
visual assessment to accurately align device 100. When correctly
aligned, flaps 124a and 124b lie snugly against the skin at the
distal end of upper arm segment 112 along the lateral and medial
sides. Any rotation of device 100, internally or externally,
results in mechanical torsion resistance from one of flaps 124a and
124b as it interacts with arm tissue from upper arm segment 112,
bending flap 124a and 124b out and pressing the tissue in. When
rotated too much the other way, the torsional resistance reverses.
When oriented correctly, torsional resistance for small rotations
of device 100 is substantially zero.
[0100] The arch also presents visual feedback to the device user of
device 100 when rotated out of position. When out of rotational
alignment, flaps 124a and 124b do not lie snugly against the skin
surface, rather, a gap appears between at least one of flaps 124a
or 124b and the skin surface of the ann. This gap is easily
identified and corrected by the user.
[0101] Further mechanical and visual feedback may be obtained from
alignment with respect to the axis of rotation of a limb joint
having one degree of freedom, which in FIG. 2, is the rotation of
the elbow joint. As the joint is rotated from extension to flexion,
the soft tissue of the forearm segment enters between flaps 124a
and 124b. When device 100 is correctly aligned on the upper arm
112, the tissue of the proximal forearm segment lightly touches
both flaps 124a and 124b. Any rotational misalignment of device 100
on the upper arm 112 results in interacting of flap 124a or 124b
with the forearm tissue, bending outwards and lifting up. The
interaction between the flaps 124a and 124b and the tissue during
elbow joint flexion presents a clear visual cue to the user of a
device rotational orientation on the upper arm segment 112.
[0102] Around the arch (formed by flaps 124a and 124b with lower
edge 116 of front panel 118), markers 128a, 128b and 128c, are
positioned by a clinician during the set-up of device 100 to
indicate with visual cue alignments to features on the skin
surface. Markers 128a, 128b and 128c are placed next to surface
markings on the skin, or local visible anatomical features
underlying the skin surface to locate and align device 100. Typical
markings that may be selected from the limb site are natural
markings on the skin surface such as beauty spots 130, skin creases
132 or anatomical features visible through the skin for example
veins 134 or tendons 136. Where natural markings are absent, marks
may be added to the body, such as by a skin marker or tattoo 138.
Additionally, the centerline 140 of device 100 may be indicated on
the arch to further help in positioning device 100.
[0103] Where appropriate, palpable bony landmarks can provide the
user of device 100 with further tactile cues for accurate alignment
of device 100. For example, the medial 142 and lateral 144
epicondyles of the humerus underlie flaps 124a and 124b. The
fingertips may be used to judge the distance between the medial
epicondyle 142 and flap 124a, and between the lateral epicondyle
144 and flap 124b. The relative positions thereof can be accurately
assessed, and fine adjustment of the location of device 100 can be
carried out accordingly.
[0104] Another preferred embodiment of the present invention, a
neuroprosthetic leg device 200 for the lower leg, is illustrated in
FIG. 3. Neuroprosthetic leg device 200, which, by way of example,
is for a right leg, is worn at the proximal end of the lower leg
segment (see FIG. 4). In a fashion that is similar to that of FES
device 100 for the upper arm (shown in FIG. 2), local site
anatomical features and bio-mechanical characteristics are used to
locate leg device 200 on to the leg segment, including the general
conical shape of the limb, local visible and palpable features in
the vicinity, as well as the rotational axis of the knee joint.
[0105] For a perceptually challenged user of leg device 200, visual
cues are integrated into the appearance of device 200 to make
obvious the orientation of the device. Front and rear panels 218
and 220, respectively, are distinguished by characteristic shapes
of convex edges 222a and 222b on the rear panel, and concave edges
215a and 215b on the front panel, as well as by colored designs,
markings and logos to give visual orientation and to distinguish
between the front and back and the top and the bottom of the
device. A handle 226 on the medial side of leg device 200 serves to
visually identify the medial side. In addition, for hemiplegic
users, when grasped in the hand on the non-plegic side of the
seated body, leg device 200 is brought around and on to the leg
following the natural trajectory of the hand, reaching an
approximately correct location of leg device 200 on the leg.
[0106] FIG. 4 is a perspective view of a preferred embodiment of
the neuroprosthetic leg device of the present invention, worn on
the lower leg and having a locator based on the tibial tuberocity.
Additional components of the locating system enable accurate
positioning. A molding 228 of the anatomical shape of the inferior
surface of tibial tuberocity 250 allows accurate location both of
the longitudinal placement of device 200 along the long axis of
lower leg segment 234, as well as the rotational orientation about
the long axis of leg segment 234. Anatomical molding 228 is
positioned by the user, abutting up against the tibial tuberosity
250, thus fixing leg device 200 accurately both the angular
orientation around leg segment 234 and the position along the
length of leg segment 234.
[0107] In another preferred embodiment, shown in FIG. 5, moldings
of other landmarks and features, in the vicinity of the placement
site of device 200, include a patella locator 240 extending from
the body of leg device 200, and abutting the inferior border of
patella 242. Optionally, an additional locator 244, molded to fit
over a malleolus 260 of an ankle joint, is also shown in FIG. 5.
While locator 244, as illustrated, is used in conjunction with a
lateral malleolus, it will be appreciated by one skilled in the art
that a locator can also be used in conjunction with a medial
malleolus.
[0108] Palpable features allow device 200 to be positioned by
tactile feedback. Bony landmarks such as tibial tuberosity 250
(best seen in FIG. 4), patella 242, or malleolus 260 may be used to
align tactile locators of leg device 200, such as patella locator
240, based on tactile feedback instead of, or in addition to,
visual feedback.
[0109] Other components of the locating system, shown in FIG. 6,
may include snug-fitting locator flaps 224a and 224b at each side
of leg device 200. Locator flaps 224a and 224b point upward from
leg device 200, utilizing knee joint axis of rotation 262 as a
locating means. Articulation of the knee joint will result in the
distal thigh segment touching the flaps 224a and 224b without
bending them when device 200 is correctly located. When incorrectly
located, one flap 224a or 224b will be bent outward by interacting
with the thigh tissue. This will present tactile feedback to the
user in the form of mechanical resistance to rotational adjustment
of device 200, or visual feedback from bending of the locator flap
224a or 224b.
[0110] An additional preferred embodiment, provided in FIG. 7, is a
locating arrangement suitable for a neuroprosthetic thigh device
300 worn on a thigh segment 310 to activate a knee joint 312. The
orientation of thigh device 300 is related to the orientation of a
seat 324 of a chair (not shown) by a flat locator surface 320 on a
posterior exterior surface of thigh device 300. While donning thigh
device 300, locator surface 320 is aligned to seat 324 of the chair
in which the user sits during donning, thereby fixing the
orientation of thigh device 300 by using seat 324 as an external
frame of reference. The user is trained to maintain a standard
seated posture during the donning of thigh device 300, thereby
constraining the orientation of thigh segment 310 about a
longitudinal centerline thereof, and locating device 300 in
orientation on to thigh segment 310.
[0111] It should be appreciated that similar types of locating
devices may be used for locating a neuroprosthesis to other body
sites. For example, a forearm/hand neuroprosthesis may be located,
with a similar flat region, on the external palmar surface of the
neuroprosthesis. This flat region locates to a flat reference plane
such as a horizontal tabletop, together with the plane of the palm
of the hand, during device donning.
[0112] Optionally, the neuroprosthetic devices may have removable
locators, as shown in FIG. 8. FIG. 8 illustrates a tubular
neuroprosthetic device 100 suitable for fitting to a conical body
limb segment (not shown). Neuroprosthetic device 100, as shown in
the drawing, is configured for activating a left arm, and is
readily converted to a right-handed device by moving locating flaps
150a and 150b from inferior edge 164 of anterior panel 160 to
superior edge 165 of the same anterior panel 160. Device 100 is
rotated through 180' and donned on the (opposite) right arm to
convert the original left-handed configuration to a right-handed
one.
[0113] In FIG. 8, locating flap 150a has an arm for detachably
sliding in and out of slot 168. This is of particular advantage in
that locating flaps 150a and 150b can be removed after the location
function has been performed, such that neuroprosthetic device 100
is not unwieldy and uncomfortable to use.
[0114] It will be appreciated that the length and width of flaps
150a and 150b can be adjusted or selected from a range of locator
sizes during the device set-up procedure, in order to conform to an
individual patient.
[0115] It may be preferable, in some cases, for the locating flaps
to remain connected to the neuroprosthetic device after completing
the locating function. FIGS. 9 shows one arrangement for moving the
locator out of the way, so that movement of the limb is not
hampered. Locating flap 150a is shown in position during the
donning of neuroprosthetic device 100 on a limb (not shown in the
drawing). Locating flap 150b is shown in a folded-away position. It
will be appreciated that various designs and configurations of the
locating flaps can be contrived by one skilled in the art,
including, but not limited to, telescopic collapsing of the
locating flap or of the arm thereof.
[0116] The above-described device, and implementation method
therefor, allow the surface electrode array to be manufactured in a
fixed position within the surface neuroprosthetic device. In sharp
contrast to the prior art, this enables pre-arranging the surface
electrode array optimally, one electrode with respect to each
other, and reduces the dependence on the high degree of skill,
artistry, and experience required of the clinician to carry out the
initial electrode set-up procedure.
[0117] The initial device set-up procedure is essentially reversed
with respect to the prior art: the device housing the entire
electrode array is placed on the limb and adjusted to the optimal
position, then locator system is positioned and attached to the
device, such that the device can be repeatably located to this
optimal position by the patient.
[0118] Generally speaking, although the invention has been
described in conjunction with specific embodiments thereof, it is
evident that many alternatives, modifications and variations will
be apparent to those skilled in the art. Accordingly, it is
intended to embrace all such alternatives, modifications and
variations that fall within the spirit and broad scope of the
appended claims.
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